The present invention relates to a microscope system for imaging an object that can be placed in an object plane of the microscope system.
The microscope system comprises at least one imaging system that provides at least one optical imaging path for imaging a field of view of the object plane.
Microscope systems of this sort are used, for example, in medical technology as surgical microscopes, to observe an object placed in an object plane.
Such an optical microscope is, for example, known from the German laid-open patent application DE 103 00 925 A1.
With respect to surgical microscopes it is generally desirable to achieve a compact construction, i.e. a small overall height and a small volume. The reason for this is that the surgical microscope should not unduly restrict accessibility to a patient by an attending physician during surgery.
As shown in FIG. 8, a surgical microscope usually consists of a Kepler telescope 82, a zoom system 83 and a main objective 84. The Kepler telescope in FIG. 8 comprises a binocular tube. The Kepler telescope 82, the zoom system 83 and the main objective 84 are arranged in series along the respective optical imaging paths 85a, 85b, guided by these elements and provide imaging an object not shown in the Figure) that is placed in an object plane 81. Afocal interfaces are provided in-between the Kepler telescope 82, the zoom system 83 and the main objective 84, in which afocal interfaces the optical imaging paths are each imaged to infinity, to provide a modular structure of the surgical microscope. As shown in FIG. 8, such microscopes are frequently built as stereoscopic microscope systems. In stereoscopic microscope systems, at least two optical imaging paths 85a and 85b are guided such that the optical imaging paths include a stereoscopic angle α, different from zero, in the object plane 81. Afocal interfaces are provided in-between the Kepler telescope 82, the zoom system 83 and the main objective 84, in which afocal interfaces the optical imaging paths are each imaged to infinity, to provide a modular structure of the surgical microscope. As shown in FIG. 8, such microscopes are frequently built as stereoscopic microscope systems. In stereoscopic microscope systems, at least two optical imaging paths 85a and 852 are guided such that the optical imaging paths include a stereoscopic angle a, different from zero, in the object plane 81.
Furthermore, a beam splitting prism, which is not shown in FIG. 8, is frequently provided between the Kepler telescope and the zoom system, to provide an optical path for co-observation.
Therefore, it is an object of the present invention to provide a microscope system wherein the imaging system necessary to provide the desired total magnification has an especially compact structure.
It is a disadvantage of conventional surgical microscopes that they have a large overall height and a large volume, dependent on a provided total magnification.
The above object is achieved by a microscope system. Preferred embodiments are defined in the dependent claims.
According to a first embodiment, the above object is achieved by a microscope system for imaging an object that can be placed in an object plane of the microscope system, wherein the microscope system comprises an imaging system containing several optical elements for providing at least one optical imaging path. The several optical elements comprise a plurality of optical lenses, through which the at least one optical imaging path passes in sequence, and which image the object plane in an intermediate image. The optical lenses are configured in such a way that the representation of the object plane in the intermediate image is demagnified to a maximum of 0.9 times, preferably to a maximum of 0.8 times, further preferably to a maximum of 0.6 times, and especially to a maximum of 0.5 times. In this respect, “demagnified to a maximum of 0.9 times” means that the representation of the object plane in the intermediate image is demagnified by 0.1 (i.e. 10) or more.
Consequently, the microscope system is capable of firstly imaging an object placed in the object plane in a demagnified way in the intermediate image. This intermediate image can then be magnified by subsequent optics, until a desired total magnification is achieved. Due to the demagnified representation of the object placed in the object plane in the intermediate image, it is possible to build the optics following the intermediate image in an especially compact way, such that the microscope system has an especially compact structure when compared to a microscope system known from the prior art providing the same total magnification.
It can be advantageous that the several optical elements of the imaging system provide at least one pair of optical imaging paths, which include a first stereoscopic angle in the object plane, wherein the optical imaging paths include a second stereoscopic angle in the intermediate image, and wherein a ratio of the first stereoscopic angle in the object plane to the second stereoscopic angle in the intermediate image is smaller than 0.9 and especially smaller than 0.8, and further especially smaller than 0.6.
Consequently, the stereoscopic angle in the intermediate image is enlarged, when compared to the stereoscopic angle in the object plane, and as a result the optical imaging paths can be separated with ease by the optics following the intermediate image, not withstanding the demagnification of an object placed in the object plane. Therefore a desired stereoscopic impression is guaranteed.
According to a further embodiment, which can be combined with the first embodiment, the above object is achieved by a microscope system for imaging an object that can be placed in an object plane of the microscope system, wherein the microscope system comprises an imaging system containing several optical elements, to provide at least one pair of optical imaging paths that include a first stereoscopic angle in the object plane. The several optical elements contain a plurality of optical lenses through which the at least one pair of optical imaging paths passes in sequence, and which image the object plane in an intermediate image. The optical imaging paths include a second stereoscopic angle in the intermediate image. A ratio between the first stereoscopic angle in the object plane to the second stereoscopic angle in the intermediate image is smaller than 0.9 and especially smaller than 0.9, and further especially smaller than 0.6.
This enlargement of the stereoscopic angle in the intermediate image, in comparison to the stereoscopic angle in the object plane, facilitates a separation of the optical imaging paths by optical elements imaging the intermediate image. Consequently, the microscope system can be built in an especially compact way, as the optical imaging paths diverge to a higher degree in comparison to the prior art.
According to an embodiment, the optical imaging paths can commonly traverse the optical lenses. In this case, the optical imaging paths can be guided in the lenses such that the intermediate image is arranged in-between two regions, in which a distance of stereoscopic axes of the optical imaging paths from an optical axis defined by the lenses, respectively, is maximized. It is not necessary that the optical axis runs along one single straight line, but it is even possible that the optical axis is folded. The stereoscopic axes are defined by the respective centers of the at least two (stereoscopic) optical imaging paths for one object point of the object that can be placed in the object plane, which object point corresponds to the center of the representation caused by the microscope system.
According to a further embodiment, the at least one optical imaging path can be guided in the lenses in a way that the intermediate image is arranged in-between two regions, in which a diameter of a beam bundle guided by the at least one optical imaging paths, respectively, is maximized.
Furthermore, a first set of optically effective surfaces of lenses can be arranged between the intermediate image and the first region of the two regions, in which at least one of a distance of stereoscopic axes of the optical imaging path from the optical axis and a diameter of a beam of light guided by the at least one optical imaging path, respectively, is maximized. This first region is arranged between the intermediate image and the object plane. Further, a second set of optically effective surfaces of lenses can be arranged between the intermediate image and the second region of the two regions, and a third set of optically effective surfaces of lenses can be arranged between the first region and the object plane. The surfaces of one optical lens may belong to one set or else to different sets.
It can be advantageous if a ratio of the total focal length (sum of the focal lengths) of the optically effective surfaces of the first set to the total focal length of the optically effective surfaces of the second set is at least 1.1, and especially at least 1.2, and further especially at least 1.4.
It can be further advantageous if a ratio of the total focal length (sum of the focal lengths) of the optically effective surfaces of the first set to the total focal length of the optically effective surfaces of the third set is between 0.2 and 0.6, and especially between 0.3 and 0.5, and further especially 0.4.
Further advantages can be achieved if a ratio of the total focal length of the optically effective surfaces of the second set to the total focal length of the optically effective surfaces of the third set is between 0.1 and 0.6, and especially between 0.2 and 0.5, and further especially 0.3.
The ratios defined above of the total focal length of the sets of optically effective surfaces can provide a demagnified representation of an object that can be placed in the object plane into the intermediate image in an especially easy way. It can be further advantageous if the ratio of the respective distances of the stereoscopic axes of the optical imaging paths to the optical axis in the first region to the respective distances of stereoscopic axes of the optical imaging paths to the optical axis in the second region is not more than 1.1 and especially not more than 1.2 and further especially not more than 1.4.
Consequently, the optical imaging paths in the first region between the intermediate image and the object plane are separated to a larger extent than in the second region behind the intermediate image. Due to the reduction of this distance it is possible to build the microscope system in an especially compact way.
To facilitate a modular structure of the microscope system, the lenses may be adapted to represent the optical imaging paths, at least in one of the regions in which at least one of the distance of stereoscopic axes of the optical imaging paths to the optical axis and the diameter of a beam bundle guided in at least one optical imaging path is maximized, to infinity.
According to an embodiment, the imaging system may comprise first, second, third and fourth mirror surfaces, for deflecting the at least one optical imaging path, wherein the at least one optical imaging path is reflected in sequence on the first mirror surface, the second mirror surface, the third mirror surface, and the fourth mirror surface. An especially compact structure of the microscope system can be achieved by this multiple deflection of the optical imaging paths.
The first and fourth mirror surfaces may include, relative to one another, an angle of between 80° and 100° and especially 90°, and the second and third mirror surfaces may include, relative to each other, an angle of between 80° and 100° and especially 90°, and the third and fourth mirror surfaces may include, relative to each other, an angle of between 50° and 70° and especially 60°. Consequently, the mirror surfaces provide a Porro-system of the second kind.
According to an embodiment the imaging system provides at least one pair of optical imaging paths that include a stereoscopic angle in the object plane, and the imaging system contains a first subsystem containing several optical lenses arranged along one common optical imaging path, which optical lenses are commonly traversed by both optical imaging paths of the at least one pair of optical imaging paths.
At least one of the second, third and fourth mirror surfaces can be arranged between optical lenses of the first subsystem along a folded optical axis of the first subsystem.
To vary at least one of the magnification of representation of the object that can be placed in the object plane, and a working distance of the microscope system, it can be advantageous if at least two lenses of the first subsystem can be displaced relative to each other along the optical imaging paths guided by the lenses.
According to an embodiment, the imaging system comprises a second subsystem containing several optical lenses, each of which are traversed by only one optical imaging path of the at the least one pair of optical imaging paths. The beams, or rays, which are respectively guided by the optical lenses of the second subsystem, define the course of the optical imaging paths in the optical lenses of the first subsystem, and thus the course of the stereoscopic axes.
To further adjust the magnification of the representation of the object that can be placed in the object plane, it may be advantageous if at least two lenses of the second subsystem can be displaced relative to one another along the common optical imaging path.
According to a further embodiment the above object is achieved by a microscope system for imaging an object that can be placed in an object plane of the microscope system, which microscope system comprises at least one imaging system for providing at least one pair of optical imaging paths, which include a stereoscopic angle in the object plane. This embodiment may be based on the embodiments described above. The imaging system comprises a first subsystem containing several optical lenses that are commonly traversed by both optical imaging paths of the at least one pair of optical imaging paths. Furthermore, the imaging system comprises a second subsystem containing several optical lenses which respectively are traversed by only one optical imaging path of the at least one pair of optical imaging paths. At least two lenses of the first subsystem and at least two lenses of the second subsystem are displaceable along one common optical imaging path relative to each other, to respectively adjust the magnification of the representation of the object that can be placed in the object plane.
Consequently, the adjustable magnification of the representation of the object that can be placed in the object plane, which magnification is achieved by the microscope system, can be split up within the microscope system in two zoom systems arranged in series, wherein the first zoom system is arranged in the first subsystem and the second zoom system is arranged in the second subsystem.
It may provide benefits if the microscope system further comprises a lighting system containing an optical lighting path for illuminating the object plane.
A microscope system having the features described above is especially suitable for use as a stereoscopic microscope, and especially as a surgical microscope, due to its compact structure.